Yangle, Voice of Bones

Yangle, Voice of Bones enters the battlefield with a number of +1/+1 on it equal to the amount of mana spent to cast it.
Vigilance, Trample
Whenever you cast a creature spell with {x} in its mana cost, destroy an artifact or enchantment an opponent controls. Return a creature from your graveyard with equal or less mana cost to the battlefield.